BARCELONA, Oct 2 (Reuters) - Prime Minister Mariano Rajoy faces Spain’s biggest constitutional crisis in decades after Sunday’s violence-marred independence referendum in Catalonia opened the door for its wealthiest region to move for secession as early as this week.

The streets of Barcelona, the Catalan capital, were quiet on Monday, but newspaper editorials said the banned referendum, in which Catalan officials said 90 percent of voters had chosen to leave Spain, had set the stage for a decisive clash between Madrid and the region.

“It could all get worse,” the moderate Catalan newspaper La Vanguardia said in an editorial after Spanish police used batons and rubber bullets to disrupt the vote, sparking violence that Catalan officials say injured around 840 people.

“We’re entering a phase of strikes and street protests ... and with more movement, more repression.”

Catalonia is a centre of industry and tourism accounting for a fifth of Spain’s economy, a production base for major multi-nationals from Volkswagen to Nestle, and home to Europe’s fastest-growing shipping port.

Catalonia’s regional leader declared late on Sunday that voters had earned the right to independence and said he would present the results to the region’s parliament, which then had the power to move a motion of independence.

Carles Puigdemont’s comments fell short of a declaration of independence, but they threw down a challenge to Rajoy, who has the constitutional power to sack the regional government and put Catalonia under central control pending fresh elections.

That would raise tensions further in the region of 7.5 million people, a former principality with its own language and culture, and potentially hurt the resurgent Spanish economy.

The euro lost a third of a U.S. cent after the vote, though it later recovered ground. Spain’s IBEX stock index was down 1.3 percent as it opened on Monday while government debt yields ticked up.

Major investment banks expect the crisis eventually to be resolved with an offer from Rajoy of more autonomy.

“We believe the risk of larger confrontations in the near-term is rising, involving at the extreme wide disruptions with potential severe economic costs,” Citibank said in a note on Monday, It did not, though, see this as the most likely outcome.

Catalan trade unions have called a general strike for Tuesday.

ALL-PARTY TALKS?

Rajoy offered to call all-party political talks on Sunday to “reflect on the future” of Catalonia, but maintained his outright rejection of independence as an option.

The Madrid government’s attempts to prevent Sunday’s referendum through the use of police force brought criticism from fellow members of the European Union, including Britain and Belgium. But there has been silence from the EU itself.

At home, the crisis does not appear to have endangered support for Rajoy’s minority national government, with mainstream parties largely backing his opposition to Catalan independence.

There was, however, criticism of his handling of the issue.

The anti-independence newspaper El Pais wrote in an editorial of Rajoy’s “absolute inability to manage the crisis since the very beginning”.

The Catalan government said 2.26 million people had cast ballots on Sunday, a turnout of about 42 percent, despite the crackdown. The results were not a surprise, given that many unionists were not expected to turn out. Opinion polls had shown around 40 percent support for independence.

In the run-up to the vote, Puigdemont had said he would move to a declaration of independence within 48 hours of a “Yes” vote. But the disruption to polling could complicate any such move.

Puigdemont called on Europe on Sunday to step in to make sure fundamental rights were fully respected.

“On this day of hope and suffering, Catalonia’s citizens have earned the right to have an independent state in the form of a republic,” Puigdemont said in a televised address.

“My government, in the next few days will send the results of today’s vote to the Catalan parliament, where the sovereignty of our people lies, so that it can act in accordance with the law of the referendum,” he said.

Rajoy offered political discussions, but said any dialogue must be held “within the law”.

“I propose that all political parties with parliamentary representation meet and, together, reflect on the future we all face,” Rajoy said in his own televised address. (Additional reporting by Angus Berwick in Sant Pere de Torello, and Adrian Croft, Sonya Dowsett, Paul Day and Julien Toyer in Madrid; Writing by Mark Bendeich; Editing by Kevin Liffey)